Manufacture of articles from steel alloys



Patented Feb. 22, i 1938 UNITED STATES PATENT OFFICE 2,109,118 MANUFACTURE OF ARTICLES FROM STEEL Friedrich Karl Nami ann, Essen, Germany, assignor to Fried. Krupp Aktiengesellschaft, Essen-on-the-Buhr, Germany No Drawing. Application March 2, 1934, Serial 4 Claims.

This invention relates to the manufacture irom steel alloys ofarticles that by their nature are subjected in use to and. must withstand the attackof, gases that attack and remove carbon.

5 The invention is particularly applicable to the which contain chromium, tungsten, molybdenum or vanadium and if desired nickel. Tests made with steel alloys containing vanadium however showed only a very slight increase of the resistance of the alloys to the attack of hydrogen. A steel alloy, for example, containing 0.25% C, 0.26% Si, 0.48% Mn, 2.08% Cr and 0.30% V lost its carbon to a depth of 3.8 mm. when'subjected to the action of hydrogen for fifty-nine hours at a temperatureof 600 C. and a pressure of 300 at. whilst for example a steel containing 0.23% C, 0.26% Si, 0.50% Mn, 1.97% Cr and 0.44% Mo under equal conditions after 300 hours showed a 30 depthof carbon removal of 2.1 mm. only. The in- .fluence of the V-content on the resistance of the steel to carbon-removing gases thus was only small, at any rate smaller than that of the molybdenum. It has been found, however, that 3 vanadium imparts to the steel a very high resistance to the attack of carbon-removing gases, if added to the steel in higher percentages than it is usual for improving mechanical properties of the steel. For, if so much vanadium is added to the steels, that the vanadium content amounts to at least the fourfold the C-content, and in all cases, more than 0.3%, its efiect on the resistance to .the action of carbon-removing gases is notably greater than the efiect 'obtained by the addition of equal percentages of chromium, tungsten or molybdenum. Besides vanadium, also the remaining elements of the V. group of the periodic table which form carbides in the steel, viz. columbiumand tantalum, impart to the steel high resistance to the attack of gases that attack and remove carbon.

The present invention therefore consists in the manufacture of articles of the class described, that is, which by their nature are subjected in use to, and must withstand the attack of, gases attached already after hours and had lost the v of the carbon content, so that a determined No. 713,925. In Germain; March -20, 1933 that attack and remove carbon, from steel alloys which contain at least one of the elements of the V. group of the periodic table which form carbides in the steel, viz. vanadium, columbium and tantalum; and if desired one or more of the elements silicon, manganese, nickel, chromium,

cobalt, molybdenum and tungsten. In the case of a. steel alloy in which the elementoi' the V. group which forms carbides in the steel is vanadium according to the invention, the vanadium content amounts to more than 0.3%

Test bars of a cross section of 10x 10 mm. made from steels of the following composition 0.09% c, 0.39% Si, 0.48% Mn, 0.62% v,

0.09% c, 0.39% Si, 0.54% Mn, 1.24% .v, 0.10% c, 0.22% 51, 01.45% Mn, 0.07% Cb, 0.09% c, 0.25% Si, 0.48% Mn, 11.70% Taafter having been exposed in a high pressure tube during 100 hours to the attack of hydrogen under pressure of 300 at. and at a temperature of 600 (3., showed no loss of carbon that could be detected when treated in the same manner were seriously carbon nearly completely after 100 hours. A particularly favorable influence of the vanadium is to be observed, if the vanadium content amounts at least about to the fourfold Also the content of columbium or tantalum may amount to about 5%. Furthermore, in order to improve the mechanical properties of the steel' alloys and their resistance to scaling and corrosion, further alloy constituentsmay be added to the alloys used according to the invention, such as silicon, manganese, nickel, cobalt,. chromium,

"tungsten and molybdenum. The total content of these elements, separate or mixed, may amount to about 30%. In general, however, a total content of not more than 15% thereof is found satisfactory. Even when these additional elements are present in the alloy, the vanadium, columbium and tantalum remain the principal factorof the resistance to the removal ofcarbon, owing to their great affinity for carbon.

It has been found particularly suitable to make use of steels according to the invention which contain carbon in an amount not exceeding 0.4%, vanadium, columbium or tantalum in anamount not exceeding 2%, molybdenum in an amount not exceeding 3%, with or without chromium in an amount not exceeding 10%. *Forapparatus for the destructive hydrogenation of oil and coal as well as for the synthesis of ammonia the following steel alloys may, for example, be used:

1. A steel alloy containing about 0.10% C, 0.30% Si, 0.50% Mn, 0.80% v. 2. A steel alloy containing about 0.08% C,

0.30% Si, 0.50% Mn, 1.0% Cr, 0.50% V. J

3. A steelalloy containing about 0.10% C, 1.5% Si, 0.50% Mn, 6.0% Cr, 0.4% M0, 0.6% X.

What I claim and desire to secure by Letters Patent is:

1. Articles which in their normal use are subjected to the attack of hydrogen at high hydrogen partial pressure and high temperature; said articles being made of a-steel alloy containing carbon in an amount not exceeding 1%; one or more elements of group V of the Periodic table which form carbides in the steel, in an amount over 0.3% and not over 5%, .but at least 4 times the amount of carbon; metal from the group-tungsten and molybdenum in an amount not exceeding 3%; chromium in an amount less than 5%; the remainder substantially all iron.

.3. A process which comprises subjecting a material to be hydrogenated to the influence of hydrogen at high hydrogen partial pressure and high temperature in a container composed. of a steel alloy containing carbon in an amount not ex- 1 ceeding 0.4%, over 0.3% and up to 2% of one or more elements of group V of the Periodic table which form carbides in the steel, metal from the group tungsten and molybdenum in an amount not exceeding 3%, and chromium in an amount less than 5%, the remainder iron containing up to 1.5% of silicon and up to 0.54% of manganese.

4. .A process which comprises subjecting a material to be hydrogenated to the influence of hy- -drogen at high hydrogen partial pressure and high temperature in a container composed of a steel alloy containing carbon in an amount not exceeding 1%; one or more elements of group V of the Periodic table which form carbides in the. steel, in an amount over 0.3% and not over 5%,. but at least four times the amount of carbon;

metal from the group tungsten and molybdenum in an amount not exceeding 3%; chromium in an amount less than 5%; the remainder iron containing up to 1.5% of silicon and up to'0.54% of manganese. 1 I j FRIEDBICH' KARL NAUMANN. 

